X-1 (poison)

"The substance is deadly in large quantities, Lord Durga. But in small quantities, it would not kill. Instead, it would concentrate in the brain tissues, causing the victim to experience a progressive deterioration of the thought processes. And the substance is also highly addictive. Once the victim grew accustomed to ingesting it in high enough doses, the abrupt withdrawal of the substance would cause the symptoms you described—wracking pain, convulsions, and death. And that, Lord Durga, is why your parent died. Not from the X-1 in his system…but from its abrupt withdrawal."

X-1 was the designation given by Myk Bidlor and his team to the poison that killed Aruk the Hutt. It had been developed by the Malkite Poisoners. Extremely rare and expensive, it preyed on the tissues of the brain, slowing a victim's thinking and making them become slow and sluggish. Victims would become addicted to the substance, over a space of several weeks or months, to such an extent that an abrupt withdrawal of the toxin would kill the addicted being.